V6 engines are disappearing even from luxury sedans like the Mercedes E-Class, which used to come standard with one. It now comes standard with a four-cylinder engine, a very small engine given the size and prestige of the E.
It’s been made stronger via turbocharging, something practically every company making luxury cars has resorted to as a way to maintain the power of a V6 without using as much gas as a V6 does. There is also pressure to produce less gas (carbon dioxide) to comply with government regulations.
But there’s something about a six and Mercedes, which just brought it back.
Not just a V6, and it uses no more gas than the standard four.
What It Is
The E-Class sedan is Mercedes’ entrant in the mid-sized luxury sedan segment. Its most immediate rival is the BMW 5-Series sedan, which is about the same size, similarly priced, and equipped.
Prices start at $54,250 for the base trim E450, powered by a 2.0-liter turbocharged four-cylinder engine driving the rear wheels.
Mercedes’ 4Matic all-wheel-drive system is available optionally, which brings the MSRP to $56,750.
The E450 comes with a turbocharged 3.0-liter in-line six, paired with a 48-volt electrical system and high-speed starter/generator. This allows the gas engine to be continuously cycled off to save gas and reduce the gasses produced. It’s also designed to eliminate any noticeable transitions, which is very important for a luxury sedan with a $62,000 base price (including the 4-Matic AWD system).
Mercedes calls this system EQ boost.
What’s New
The new 3.0-liter in-line six (and 48-volt starter/generator system) replace the previous 3.0-liter V6 as the E’s optional drivetrain.
Al trims get an upgraded Mercedes-Benz User Experience (MBUX) infotainment system, revised exterior styling, and a new-design steering wheel.
What’s Good
- Horsepower is maintained, gas mileage goes up.
- The price goes up only slightly.
- Irrespective of what’s under the hood, the E sedan has a beautifully finished, open-feeling cabin surpassed only by an S-Class cabin, and that not by much.
What’s Not So Good
- The new six should never be cycled off.
- Gas mileage gains are slight.
- The mouse pad controller is hard to use accurately while driving.
Under The Hood
The E comes standard with a 2.0-liter four, which would have been considered an unusual engine to find under the hood of a $50,000 luxury sedan a decade ago.
Back in 2011, the Mercedes E came standard with a 3.5-liter V6, which didn’t need a turbo to make its 268 horsepower. The ’21 E’s 2.0-liter four needs one to make its 255 horsepower.
More accurately, it needs to burn (and emit) less gas for Mercedes to continue selling cars like the E without entirely electric drivetrains. The turbo four is a compromise between the all-electric and thus zero gas burning (and emitting) and the too much gas burning (and emitting) V6, RIP.
The gas mileage difference isn’t much, however.
The current E’s turbo-four rates 22 city, 31 highway while the 2011 E’s 3.5-liter V6 rated 17 city, 25 highway—a picayune difference for a car in the E’s class. But Mercedes has to worry about gas emissions as much as gas mileage and displacement fines for exceeding 2.0-liters of engine back in Europe.
This is why there is a small four as standard now rather than the previous V6.
In terms of tangible benefit to the buyer of a new E, the good news is that the turbocharged four produces more torque and sooner. It makes 277 ft. lbs. at 1,800 RPM vs. the RIP’d V6’s 258 ft.-lbs. at 2,400. This makes it feel more robust in the low and mid-ranges than the rest-in-peace V6.
So equipped, an E sedan gets to 60 in about 6 seconds, which is about the same as the old V6 E.
The big news is the return of the straight-six.
Mercedes was once famous for such powerplants, which propelled iconic models like the 300SL back in the 1950s and ’60s.
Straight sixes have the virtue of being almost as smooth as an electric motor while making sounds no electric motor can make. This is because the in-line six layout is inherently balanced—no side-to-side vibrations. For that reason, it also doesn’t need a heavy external balancer to tamp down the vibrations, which means the reciprocating assembly (crank, rods, and pistons) are lighter and so rev freer.
It is the perfect powerplant for a sophisticated luxury sedan.
But a six, whether straight or in a “v,” uses and produces more gas than a four, making it hard to offer the additional cylinders, whether in-line or arranged in a “v.”
Mercedes’ solution is to turn all of them off as often as feasible. And back on as necessary, without the obvious stop/start cycling that would render the inherent smoothness of the in-line six as irrelevant as the great taste of the food you can’t eat.
The EQ system can be described as a hybrid system, and the intent is the same, but the means toward that end are different.
Most hybrids have an electric motor, which to one degree or another, can propel the car. The Benz has an integrated starter/generator sandwiched in-between the engine and the nine-speed automatic transmission.
When the engine is running, it is spinning the flywheel-mounted generator, creating a great deal more electricity (48 volts) than a much smaller alternator spun by an accessory drive belt.
When the engine’s power isn’t needed (as during coasting/deceleration), the system turns the engine off.
When the engine’s power is needed again (for acceleration), it is spun back to life by the flywheel starter. It is much more powerful by dint of leverage with electricity than a standard starter motor bolted to the flywheel, allowing for virtually instantaneous and seamless re-starts.
There’s also a slight power boost relative to last year. The output of the EQ-boosted straight-six is exactly the same 362 horsepower and 369 ft.-lbs. of torque as that produced by the old V6 by itself. But the new drivetrain’s peak torque is made slightly sooner, at 1,600 vs. 1,800 RPM.
It’s slightly quicker, too, than last year’s V6-only E-Class—getting to 60 in about 4.5 vs. 4.6 seconds.
There’s another slight difference as well.
The EQ-boosted Benz rates 23 city, 30 highway, a slight improvement over the previous V6 E’s 20 city, 28 highway.
But it’s the difference you can’t see that makes the six possible.
By cycling it off as often as possible, it keeps the quantity of gas the six produces low enough not to cause problems with federal regulators.
It is why other car companies are resorting to the same tech work-arounds such as Jaguar, which uses a similar system in the new F-Pace—BMW, too.
There aren’t yet “greenhouse gas” emissions regulations in the U.S. But they are coming, and Mercedes and the rest are being proactive.
And the upside is they’re able to sell engines like this new six.
On The Road
Mercedes touts the seamless transitions and the quiet of the EQ-boosted drivetrain, but it’s the sound of the six that sells this thing. The shame is that so much work was put toward making it silent and hiding it.
Underneath that ugly plastic engine, cover lies one of the most beautiful engines ever put into a car. Instead of showing it off, Mercedes chose to make it look like every other engine by burying it under a shroud that looks the same as the ones covering up ordinary engines.
It deserves better.
In-line sixes are uncommon due to length limits. Generally, small cars are out—there’s just not enough room. And front-drive cars are out, too, for the same reason.
But the thing which defines them is their song, which you’ll hear when you give the E enough pedal to overcome the silent-drive EQ system and the acoustic muffling.
Select Sport+ mode using the little toggle to the left of the mouse trackpad on the center console. The flatscreen gauges go red backlit, but it’s not the visuals that excite or even the speed which ensues.
It’s that sound.
Nothing else makes it. And that, absent any noticeable vibrations, is what makes a straight-six something special, to be savored.
The analogy is similar to a wagyu steak vs. an ordinary ribeye. Both are good. But one is a rare treat for the person lucky enough to be able to afford it.
There is something else that makes the E450 special—it is soft.
The seats, the surfaces, and the ride. Not a car for the corners but a car driving for hours, whether in traffic or headed cross-country.
The feel, including the available massaging seats, will make you feel special, which is ultimately the point of spending $60k-plus on any car.
Mercedes put a lot of work toward creating this ensemble, including the visual of the world outside the car, which you can see and feel as a part of because of all the glass. Many new cars make you feel as though you are driving a bathtub; the doors are high, the glass almost looks like slits. This is done in part as a cheap way to score well in side-impact crash testing.
But how “safe” is a car you can’t see out of directly?
Driving the E is relaxing as well as inspiring. It has the legs of a Kenyan marathon runner, the lungs of Pavarotti, and the softness of your favorite sofa on a warm summer’s day.
In a word, it is special because there aren’t many like it under the hood or otherwise.
At The Curb
The E-Class, which is Mercedes’ mid-priced, mid-sized luxury sedan, now comes with or offers essentially the same amenities that used to be exclusive to the S-Class, Mercedes’ top-of-the-line (and full-sized) sedan.
These include an entirely flatscreen panel, not just for the main gauges but also for the secondary infotainment displays. The functional advantage to this layout is that more can be displayed because you can toggle various displays.
Physical gauges limit what can be displayed. It also looks razzle-dazzle, though there is a pratfall there — because flat-screen displays are not inherently expensive to put into a car, which is why they are now commonplace in ordinary cars.
This takes away some from the razzle-dazzle.
But ordinary cars do not and cannot offer the creamy-soft leather and other such that cannot be made inexpensive and abounds inside the E.
You will also notice other points of departure, such as the beautiful paint under the hood. In ordinary cars and some luxury cars, the paint in such areas is dull because it wasn’t clearcoated to save a few bucks per car. This makes a car look cheap and makes you feel less if you paid $60k-plus for it.
The one thing you don’t get for your $60k-plus is the rearseat legroom and trunk size of the S-Class. Instead of the S-Class’s limousine-like 43 inches of legroom for the back seat occupants, there are only 36.2 inches, and the E’s trunk is smaller. Remember, so is the price by about $50,000.
The Rest
You don’t have to buy the six to get everything else Mercedes offers in this class. This could include the massaging (and bolstering seats) or the heated arm-rests and the center pad, the superb Burmester audio system, the adaptive suspension, panorama sunroof, surround-view camera, or the plethora of luxury/convenience and driver-assistance tech that’s there for the opting.
A nice feature that end-runs the mouse trackpad input on the center console is the voice-command system. You can change the radio station, make a call and get the car to obey a plethora of commands without having to touch anything. This dramatically reduces both annoyance and distraction.
Mercedes also thoughtfully includes redundant mechanical inputs for essential functions, such as the volume for the sound system, which can be rolled up or down using a very happily tactile thumbwheel on the center console.
There are similarly tactile switches on the center stack to up-and-down the heat/cooling, fan speed, and so on.
Finally, Mercedes deserves praise for only slightly increasing the price of the new E450 relative to the previous (2020) V6-powered E-sedan, which stickered for $61,550 vs. $62,000 for the new straight-six and EQ-boosted E450.
The Bottom Line
Mercedes has figured out a way to let you have the cake the government didn’t want you to eat without charging you an outrageous sum to get it, either.
Eric Peters lives in Virginia and enjoys driving cars and motorcycles. In the past, Eric worked as a car journalist for many prominent mainstream media outlets. Currently, he focuses his time writing auto history books, reviewing cars, and blogging about cars+ for his website EricPetersAutos.com.
Editor’s Note: The opinions expressed in this article are those of the author.
